Protective switch device foe a sxwk  plug



June 22, 1965 F. ROSE ETAL PROTECTIVE SWITCH DEVICE FOR: PLUG Filed Dec. 10, I962? Eil m FRANK L. ROSE TIMOTHY A. BRENNAN ATTORNEY United States Patent 3,190,979 PROTECTIVE SWITCH DEVICE FOR A SPARK PLUG Frank L. Rose, 51 Redspring Road, and Timothy A. Brennan, 63 Andover St, both of Andover, Mass. Filed Dec. 10, 1962, Ser. No. 243,389 4 Claims. (Cl. 20052) This invention relates to protective devices and more particularly to protective devices for the ignition system In recent years there has occurred a rapid increase in the use of small gasoline motors in business and in the home. In many instances these motors have been used in devices that are dangerous in the hands of the unskilled andthe careless. In particular, these motors have been widely used in lawn mowers for rotating a cutting blade at extremly high velocities and in portable saws. Numerous accidents have occured by these tools starting up unexpectedly. In addition, when left unattended, children have been known to start these hazardous tools.

It is an object of the invention to provide switch for rendering the gasoline motor inoperable.

It is another object of the invention to provide an attachment to small gasoline motors which renders them inoperable.

It is another object of the invention to provide an attachment for sp'arkplugs which opens and closes the electrical circuit for energizing the sparkplugs.

It is still another object to provide a key actuated switch means which is easily attached to sparkplugs for opening and closing the electrical circuit for energizing the sparkplugs.

In accordance with the invention a protective device adapted to be used in a sparkplug circuit which includes a sparkplug having a high voltage terminal and a high voltage lead which is normally connected to said high voltage terminal comprises switch means for making and breaking an electrical connection between the high voltage terminal and said high voltage lead. The switch means may be placed in series between these .two points or preferably may be used to ground out the high volt age terminal to make the sparkplug inoperative. The protective device also includes means for securing the switch means to a sparkplug.

The novel features that are considered characteristic of the invention are set forth in the appended claims; in the invention itself, however, both as to its organization and method of operation, together with additional objects and advantages thereof, will best beunderstood from the following description of the specific embodiments when read in conjunction with the accompanying drawings in which:

FIGURE 1 is a sectional view of a protective device embodying the principles of the invention;

FIGURE 2 is a bottom view of the switch means; and

FIGURE 3 is a fragmentary view of an alternate terminal connection.

Referring to FIGURE 1 there is shown a sectional view of a protective device 10. It includes a sleeve 11, made preferably from plastic or another suitable insulator. One end of sleeve 11 includes a lower compartment 11a dimensioned to fit over and receive a sparkplug 12 shown in phantom.

An insulated partition 14 which includes a central metal r/ of small gasoline motors.

threaded into a complementary threaded hole 19 formed in the partition 14 and the metal insert 16.

The upper compartment 11b of the sleeve 11 includes a. lock assembly comprising preferably a cylinder lock 21 which actuates a switch means 22.

Referring to FIGURE 2 there is shown a bottom view of the switch means 22. 'It includes an S shaped strip of metal 28 which extends across one diameter of a disc 29 formed from an insulator. The strip 28 terminates in a pair of opposing terminals 31 and 32. The disc 29 is secured to the lock 21 by any suitable means.

A strap 23 extends downwardly from a terminal 24 on sleeve 11. The strap 23 is adapted to contact the base 12b of the sparkplug 12.

. An L shaped strap' 26 interconnects the metal insert 16 with a second terminal '27 which extends through the a wall of sleeve 11 to a terminal 30 that is adapted to insert 16 having a central threaded hole 17 is Positioned receive the high voltage lead which normally is connected to. the high voltage terminal 12a of the sparkplug 12.

Referring to FIGURES 1 and 2 it is seen that high voltage terminal 12:: is coupled through strap 26 through switch means 22 to strap 23 and throughstrap 23 to base 12b. The sparkplug is thus shorted out, electrically, and inoperative.

If the lock is actuated to rotate the switch means 22 the shorting connection through switch means 22 is broken and high voltage supplied to terminal 27 is applied through strap 26 to the high voltage terminal 12a. The sparkplug is thus in an operative condition.

Referring to FIGURE 3 illustrates an alternative method of utilizing switch means 22, in a series connection. High voltage applied to terminal 27 is coupled through switch means 22 to strap 23:: and then to the high voltage terminal 12a. When the switch means 22 is rotated as aforementioned, the series connection is broken placing the circuit in an inoperative condition.

Thus, inoperativeness can be achieved by breaking a series circuit (FIGURE 3) or shorting out the sparkplug (FIGURE 1).

The various features and advantages of the design and construction disclosed are thought to be clear from the foregoing description. Various other features and advantages not specifically enumerated will undoubtedly occur to those versed in the art, as likewise will many variations and modifications of the preferred embodiments of the invention illustrated, all of which may be achieved without departing from the spirit and scope of the invention as defined by the following claims.

We claim: t

1. A protective device adapted to be used in a'sparkplug circuit having a high voltage terminal normally connected to a high voltage lead and a base comprising:

(a) a sleeve divided into upper and lower compartments by a non electrical conducting partition having a central metal disc including a central threaded hole adapted to receive said high voltage terminal;

(b) first terminal means insulatingly mounted on said sleeve and extending into said upper compartment, said first terminal means being electrically connected to said metal disc and including means for receiving said high voltage lead;

(0) electrical conducting means secured to said sleeve terminating in said upper compartment spaced from said first terminal means and extending through said partition into said lower compartment for contacting said base; and

(d) switch means mounted in said upper compartment for making and breaking an electrical conducting path between said first terminal means and said electrical conducting means.

2. A protective device as described in claim 1 in which said switch means comprises a rotatable disc having spaced terminal means electrically joined, said spaced terminals for complementary engagement of said first terminal means and said electrical conducting means for making and breaking contact with said first terminal means and said electrical conducting means.

3. A protective device adapted to be used in a sparkplug circuit having a high Voltage terminal normally connected to a high voltage lead, an insulator and a base comprising: 7

' (a) an insulating sleeve including an upper and a lower compartment separated by an electrical insulating partition including a central hole, said lower compartment dimensioned to fit over a sparkplug;

(b) a metal insert in said central hole having a central threaded hole adapted to receive said high voltage terminal;

(c) first and second opposing terminal means mounted on said sleeve in said upper compartment, said second terminal means including means for receiving :said high voltage source;

((1) a first electrical conducting means electrically coupling said metal insert to said second terminal means;

(e) second electrical conducting means connected to said first terminal means extending into the lower compartment and adapted to contact said base; and

(f) switch means mounted in the upper compartment for making and breaking an electrical contact between said first and second terminals.

4. A protective device as described in claim 3 in which said switch means comprises'a rotatable disc having a strip of metal extending across one diameter thereof terminating in diametrically opposed terminals for making and breaking contact with said first and second terminals.

References (Zited by the Examiner UNITED STATES PATENTS 1,250,975 12/17 Cooper 20044 1,293,309 V 2/19 Benjamin 20051.17 1,353,959 9/20 Holst 200-44 1,658,599 2/28 Hohl l. 2 OO155 BERNARD A. GILH EANY, Primary Examiner. ROBERT K. SCHAEFER, Examiner. 

1. A PRTECTIVE DEVICE ADAPTED TO BE USED IN A SPARKPLUG CIRCUIT HAVING A HIGH VOLTAGE TERMINAL NORMALLY CONNECTED TO A HIGH VOLTAGE LEAD AND A BASE COMPRISING: (A) A SLEEVE DIVIDED INTO UPPER AND LOWER COMPARTMENTS BY A NON ELECTRICAL CONDUCTING PARTITION HAVING A CENTRAL METAL DISC INCLUDING A CENTRAL THREADED HOLE ADAPTED TO RECEIVE SAID HIGH VOLTAGE TERMINAL; (B) FIRST TERMINAL MEANS INSULATINGLY MOUNTED ON SAID SLEEVE AND EXTENDING INTO SAID UPER COMPARTMENT, SAID FIRST TERMINAL MEANS BEING ELECTRICALLY CONNECTED TO SAID METAL DISC AND INCLUDING MEANS FOR RECEIVING SAID HIGH VOLTAGE LEAD; (C) ELECTRICAL CONDUCTING MEANS SECURED TO SAID SLEEVE TERMINATING IN SAID UPPER COMPARTMENT SPACED FROM SAID FIRST TERMINAL MEANS AND EXTENDING THROUGH SAID PARTITION INTO SAID LOWER COMPARTMENT FOR CONTACTING SAID BASE; AND (D) SWITCH MEANS MOUNTED IN SAID UPPER COMPARTMENT FOR MAKING AND BREAKING AN ELECTRICAL CONDUCTING PATH BETWEEN SAID FIRST TERMINAL MEANS AND SAID ELECTRICAL CONDUCTING MEANS. 